The surfaces of a wall of a fusion reactor that face the plasma or the surface of an X-ray anode experience not only high temperatures but also high mechanical, thermocyclic stresses that may lead to crack formation or else to melting of the materials. In both applications, refractory metals, (in particular, tungsten), are used.
The tape casting process for refractory metals is known from WO 2007/147792 A1 for producing planar components in the case of tungsten-heavy metal alloys. WO 2007/147792 A1 discloses a process for producing flat, shaped objects composed of a tungsten- or molybdenum-heavy metal alloy, in which a slip for tape casting is produced therefrom, a sheet is cast from the slip and the sheet is dried and subjected to binder removal and sintered in order to obtain the shaped object. The term tungsten- or molybdenum-heavy metal alloy refers, in the sense of WO 2007/147792 A1, to materials selected from the group consisting of tungsten-heavy metal alloys, tungsten, tungsten alloys, molybdenum, and molybdenum alloys. Tungsten-heavy metal alloys include from about 90% by weight to about 97% by weight of tungsten or tungsten alloys. The remainder is made up of binder metals. As metallic binders, mention may be made primarily of the elements Fe, Ni, and/or Cu in proportions of greater than 1% by mass. The metallic binders provide simplified production processes by relatively low sintering temperatures, improved mechanical properties, in particular ductility, and improved workability, e.g., a better ability to undergo cutting machining. These materials are aimed at use in applications for radiation shielding, with a high density of the alloys being of primary importance.